1. Field of the Invention
Embodiments of the invention relate to the field of circuit protection devices. More particularly, the present invention relates to a fuse assembly employing a post arrangement that is easier to manufacture and provides a built-in insulating configuration with the fuse.
2. Discussion of Related Art
Fuses are used as circuit protection devices and form an electrical connection between a power source and a component in a circuit to be protected. In particular, a fuse may be configured to protect against damage caused by an overcurrent condition. A fuse is constructed to physically open or interrupt a circuit path and isolate electrical components from damage upon the occurrence of specified overvoltage and/or overcurrent conditions in the circuit.
Electrical systems in vehicles typically include a number of these types of circuit protection devices to protect electrical circuitry, equipment, and components from damage caused by these conditions. For example, power sources (e.g. batteries) in vehicles utilize a fuse fitted over a terminal post to which a ring terminal of an electrical cable is connected. A nut is usually threaded onto the post to keep the ring terminal and fuse in position. When an excess current condition exists, the fuse on the terminal post protects the components connected to the power source from this excess current. Unintended shorting occurs when the ring terminal comes into direct electrical contact with the post rather than through the fuse. To overcome this problem, an insulating nut fitted over the post has been used to isolate the fuse and the ring terminal to prevent current from bypassing the fuse and damaging the protected circuit.
In certain applications, a single source of power may be shared with a plurality of these fuse arrangements to distribute power to multiple circuits. For example, FIG. 1 is a side cross-sectional view of a fuse assembly 10 illustrating a housing or block 20 from which a post 25 extends and on which fuse 30 is mounted. A ring terminal 40 is fitted over post 25. Ring terminal 40 is connected to a power cable 41 to supply power to an electrical circuit to be protected. Ring terminal is configured to make electrical contact with an upper terminal of fuse 30, but is insulated from post 25. In this configuration, power is supplied to a bus bar 45 disposed in block 20 which is connected to a lower terminal of fuse 30. In this manner, fuse 30 connects the bus bar 45 with ring terminal 40 via fuse element 35. When an overcurrent condition occurs, the fuse element 35 opens or otherwise prevents the flow of current from the bus bar 45 to ring terminal 40 thereby protecting the electrical circuit. Post 25 is molded within block 20 which is typically made from plastic. Unfortunately, by molding one end of post 25 into block 20, additional manufacturing steps and associated costs are incurred. Accordingly, there is a need to provide a fuse assembly that includes a post or terminal portion that is easier to manufacture and provides an insulating configuration to prevent unnecessary short circuits. In addition, vehicle electrical system complexity is increasing which consequently increases the number of electrical circuits to be protected therein. This necessitates the need for more and more fuse elements. However, there is a conflicting interest to keep such protection circuits compact, light weight and easily replaceable to conserve valuable vehicle space and weight footprints. It is with respect to these and other considerations that the present improvements have been needed.